Package material and packaged paper sheets

ABSTRACT

A packaging material includes a holding part that holds a plurality of recording sheets in a bundle without holding at least one end of the recording sheets and an extending part that extends from the holding part so as to cover at least part of one outer surface at the one end of the recording sheets that are held in the bundle by the holding part, with a friction coefficient of an inner surface of the extending part that contacts the recording sheets being approximately equal to a friction coefficient of the recording sheets. By packaging recording sheets with this packaging material, a pickup roller can come into contact with the end of the recording sheets and pick up the recording sheets one at a time while the recording sheets are still in a bundle by the holding part. In addition, the extending part is present as an underlay between the bottom plate and the final recording sheet, so that the recording sheets can be picked up one at a time right up to the final recording sheet.

TECHNICAL FIELD

[0001] The present invention relates to an art for packaging and supplying a plurality of recording sheets in a bundle.

RELATED ART

[0002] The recording sheets used by a printing apparatus, such as a printer, are supplied having been packaged using wrapping paper and are taken out of the wrapping paper before being set in the printer. Recording sheets that are affected by the environment in which they are stored, such as photosensitive sheets and heat sensitive (thermal) sheets, are supplied having been inserted into a bag made of a light-blocking material, with only the required number of sheets being taken out of the bag and set in the printer. The remaining sheets are kept in the packaging.

[0003] In a printing apparatus, such as a printer, a copier, or a fax machine, in which a pickup roller picks up recording sheets (cut paper or cut recording sheets) one at a time and supplies the sheets to the printing mechanism, a common problem is that the final few sheets that are stored in the sheet cassette or the sheet storing space are picked up together. This problem can lead not only to the wasteful use of recording sheets but also to printer jams and deterioration in print quality. This problem is thought to be caused mainly by only the final recording sheet coming into direct contact with the base, the lifting plate, or the bottom plate of the sheet cassette or the sheet storing space. The friction coefficient of the surface of the base or these plates differs from the friction coefficient of the recording sheets, resulting in insufficient friction, so that the final few recording sheets that are stacked on top of one another cannot be separated and end up being picked up together. For this reason, a material, such as cork or rubber, for raising the friction coefficient is stuck onto the surface or inner surface of the base or the plates so that the recording sheets can be picked up one at a time right up to the final sheet.

[0004] However, after the printing apparatus has been used for a certain period, the covering, lining or coating material on the surface of the plates becomes worn away by friction with the recording sheets, which can result in a fall in the friction coefficient and in the plates bare. Accordingly, in order to transport the recording sheets reliably over a long period, at least a part of the plate that faces the pickup roller has to be covered with a sufficiently thick material and the performance of the surface must be maintained even if there is abrasion.

[0005] In a large printer or a desktop-size printer that can print on regular-size recording sheets, such as A4 size (210 mm by 297 mm), space is available in a sheet cassette or a sheet storing space. Accordingly, it is easy to attach a material with sufficient thickness to the bottom plate and so improve the friction coefficient. However, since abrasion cannot be avoided, such performance cannot be maintained indefinitely. In a small printer suited to portable use whose thickness is only a few centimeters or a few millimeters, there is not enough space to attach a material that is worn away by abrasion. In addition, such a slimline printer can store only a few recording sheets, so that it is necessary to make reliable use of the recording sheets right up to the final sheet.

[0006] It is an object of the present invention to provide a technique or an art whereby over a long period of time a printing apparatus, such as a printer, that picks up and uses cut sheets can reliably use the cut sheets right up to the final sheet. In particular, it is an object of the present invention to provide a technique whereby cut sheets right up to the final sheet can be reliably used even in the kind of handy-sized slimline printer described above that can be easily carried about by the user.

DISCLOSURE OF THE INVENTION

[0007] The recording sheets that are used in a compact, slimline printer suited to portable use are A6 (105 mm×148 mm) size or smaller, such as small sizes like A7 (74 mm×105 mm) or A8 (52 mm×74 mm). Compared to regular-size sheets of A4 size or larger, it is difficult to arrange such recording sheets into a bundle or to line up the ends of such recording sheets. If the corners become even just slightly bent, problems occur when picking up the recording sheets or feeding the recording sheets within a printer. Also, with small-size recording sheets, there is little space in a sheet cassette or sheet storing space for the recording sheets, so that it is not easy to insert a plurality of recording sheets inside such a cassette or space without the sheets being tilted or having their edges in an unaligned state. The inventors of the present invention provides packaging the number of recording sheets that can be set in the storing space or sheet cassette of a printer and setting such sheets in a packaged state without unbundling the sheets. By setting one part of such a package between the final sheet in the recording sheets and a plate as an underlay, the inventors made it possible to prevent the final sheet from directly contacting the plate. By providing the part used as the underlay with a suitable friction coefficient, the inventors also made it possible to reliably pick up recording sheets one at a time right up to the final recording sheet.

[0008] That is, the packaging material according to the present invention includes: a holding part that holds a plurality of recording sheets in a bundle without holding at least one end of the recording sheets; and an extending part that extends from the holding part so as to cover at least part of one outer surface at the one end of the recording sheets that are held in the bundle by the holding part, wherein a friction coefficient of an inner surface of the extending part that contacts the recording sheets is approximately equal to a friction coefficient of the recording sheets. With packaged sheets (a sheet package) in which the recording sheets are held by this packaging material, the recording sheets are held, apart from at the one end of the recording sheets. Accordingly, if the number of recording sheets that can be received at a time into a printer are held in this packaging material, recording sheets are held in a bundle in the holding part and the recording sheets can be set in a printing apparatus such as a printer with the end of the recording sheets that is not held as the sheet feeding side. A pickup roller contacts the end part of the recording sheets that are held in a bundle in the holding part and can pick up the recording sheets one at a time. Even recording sheets that are smaller than a regular size become easy to handle, and users are free from the burden of having to line up the recording sheets. At times such as when the sheets are transported by the pickup roller, bending and folding of the end part of the sheets, which cause printer jams, can be avoided.

[0009] The packaging material and sheet package according to the present invention also include an extending part that extends to cover at least part of an outer surface of the one end of the recording sheets that are held in a bundle in the holding part. Accordingly, when the recording sheets are set in a printing apparatus while still being held in a bundle by the packaging material, the extending part is present as an underlay between the final recording sheet and the base of the sheet storing space or sheet cassette, or between the final recording sheet and a member such as a bottom plate or lifting plate that presses up the recording sheets to the pickup roller. This means that the environment or conditions for the generation of a frictional force for the final recording sheet are the same as the environment or conditions for the recording sheets in the middle of the bundle, so that the recording sheets can be reliably used right up to the final recording sheet. The packaging material is replaced at the same time as the recording sheets, so that there are no problems such as the wearing away of members and changes in the friction coefficient due to abrasion.

[0010] In this way, a suitable friction coefficient for holding the final recording sheet can be maintained by the extending part of the packaging material that is used as an underlay, so that there is no need to provide a printing apparatus or sheet cassette with a member for maintaining the friction coefficient. In addition, the outer surface of the outermost recording sheet is covered by the extending part of the packaging material, so that even if a bottom plate is not provided, an elastic member such as a spring still does not come into direct contact with the recording sheets. Accordingly, the recording sheets are not damaged even if pressure is applied by only an elastic member such as a spring, so that other members, such as a bottom plate, for covering the elastic member can be omitted. This means that when the packaging material of the present invention is used, a slimmer compact printer that is suited to portable use can be provided, and the cost of such a printer can be reduced. At the same time, by using a sheet package that uses the packaging material of the present invention, recording sheets can be reliably used one at a time right up to the final recording sheet, so that the limited number of recording sheets that are stored in a slimline, compact printer become effectively used.

[0011] When the pickup roller is capable of moving up and down, the position of the final recording sheet in the thickness direction does not change. This means that the extending part that forms the underlay does not need to move. However, when the pickup roller is fixed, it is necessary to change the position of the final recording sheet so that this recording sheet presses the pickup roller. For this reason, it is preferable for the extending part to be able to move in the thickness direction so that pressure applied by a plate spring or the like can be easily transmitted to the recording sheets. Therefore, it is preferable for the extending part to be connected to the holding part so that the position of the extending part in a thickness direction of the recording sheets in the bundle by the holding part changes. As one example, by connecting the extending part to the holding part via a fold or a part with reduced thickness, it is possible to make it easy for the extending part to bend with respect to the holding part.

[0012] By providing cuts along at least part of the side edges of the extending part so that the extending part can move independently of the holding part, the radius of rotation when the extending part bends can be increased, so that the position of the extending part with respect to the pickup roller can be prevented from changing significantly when the extending part has moved in the thickness direction of the recording sheets.

[0013] The easiest way of making the friction coefficient of the inner surface of the extending part the same as that of the recording sheets is to make at least the extending part out of paper. It is also possible to make the extending part or the entire packaging material out of plastic or the like and then to adjust the friction coefficient of the inner surface of the extending part. It is also possible to make not just the extending part but the entire packaging material out of paper, such as recycled paper. When considering the disposal of the packaging material once the recording sheets have been used, a packaging material that is made of paper is environmentally friendly, so that a packaging material that is easy to dispose of can be provided. It is also possible for the packaging material to be supplied in a form where the packaging material is folded up after the recording sheets are used and then sent back to the supplier so as to make recycling possible.

[0014] In order to protect the recording sheets while recording sheets are being stored or fed right up until the recording sheets are set in a printing apparatus, it is preferable for the packaging material to include, in addition to the holding part and the extending part, a cover part that covers the one end that is the sheet feeding direction end of the recording sheets that are held in the bundle by the holding part. The cover part makes it possible to hold the end part of the recording sheets that are picked up right up until the recording sheets are set in a sheet cassette or the storing part of a printing apparatus, and so can prevent problems such as printer jams.

[0015] The cover part may be formed of a different member to the holding part and extending part. The cover part may be joined to the holding part and/or extending part, and it may be possible to separate the cover part from the holding part and also the extending part of the packaging material. To make it easy to separate the cover part, it is preferable to perforate the boundary of the cover part. Separating the cover part can be made even easier by providing two perforated lines that form a belt-like part at this boundary.

[0016] In addition, since the packaging material according to the present invention can almost entirely cover the bundled recording sheets with the holding part, the extending part, and the cover part, the entire recording sheets can be protected from damage, dust and also heat during transportation and storage. In order to dissipate static electricity due to friction when recording sheets are picked up and so prevent dust from becoming attached and eradicate detrimental effects on the adhesion characteristics of ink or toner in a printer mechanism, it is preferable for the extending part and the holding part to be made of conductive members. In the case of paper, such conductive members can be realized by mixing in a conductive constituent such as carbon.

[0017] In the sheet package of the present invention, the extending part extends out from the holding part like a tongue, with this extending part being set on the opposite side to the pickup roller. This means that even if there are no indications of the front and the rear, the user can still easily know the correct side for setting the sheet package in a printing apparatus. Accordingly, users can set recording sheets, such as heat sensitive sheets that have a predetermined front and reverse, without mistaking the front for the reverse. In addition, the outer surface of the holding part and/or extending part may be used as a region for indicating the orientation for setting the recording sheets in a printing apparatus and as a region for indicating various details for the recording sheets, usage conditions, manufacturer name, and printing apparatus information, such as a list of compatible printers. Since the packaging material remains after all of the recording sheets have been used, the specifications of the recording sheets can be checked at any time. The user can also be encouraged to purchase a sheet package that is covered with the same packaging material, resulting in a promotional effect. For sheet packages that are stored in a compact printer for portable use and the like, the sheet storing space in a printer is small and slimline. Sheet packages that store around tens recording sheets and have a thickness of a few millimeters or less can be used effectively. While small-size recording sheets, such as A7 or A8 size sheets, that are difficult to handle can be packaged to make setting easy, in order to paste together box-shaped packaging materials that have a length and width of a few centimeters and a thickness of a few millimeters or less, there are cases where it is difficult to provide pasting margins of sufficient size or sufficient area for bonding. For this reason the holding part of the packaging material of the present invention may be divided into a first part that covers an upper surface of the recording sheets held by the packaging material and a second part that covers a lower surface of the recording sheets, with at least part of the edges of the first part and the second part extending outwards and being stuck together, so that margins of sufficient area for pasting can be realized. These edges that extend outwards can be used as marks showing the orientation for setting the sheet package, and the sheet storing part of a printer may have a construction where the sheet package cannot be set unless the edges of the packaging material that extend outwards are set correctly.

[0018] In a case where cuts for allowing the extending part to move independently of the holding part are provided, it is preferable to provide a cover part that covers the recording sheets that are held in the bundle by the holding part from a periphery of the end of the recording sheets up to at least the cuts, thereby preventing dust, etc., from entering via the cuts during storage or transportation. Here, the extending part may become exposed when the cover part is separated from the holding part.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 shows a packaging material according to an embodiment of the present invention when looking from the upper surface side.

[0020]FIG. 2 shows the packaging material shown in FIG. 1 when looking from the rear surface side.

[0021]FIG. 3 shows the packaging material shown in FIG. 1 when the cap-shaped part has been separated.

[0022]FIG. 4 shows how recording sheets are stored in the packaging material shown in FIG. 1 with the cap-shaped part having been removed.

[0023]FIG. 5 is a view, partly in cross-section, showing the sheet package shown in FIG. 4 after the sheet package has been set in a printer.

[0024]FIG. 6 is a view, partly in cross-section, showing a state where there are few recording sheets left in the sheet package.

[0025]FIG. 7 is a model of an environment in which the final few recording sheets are picked up when the packaging material of the present example is used.

[0026]FIG. 8 is a perspective view of a different packaging material according to the present invention looking from the upper surface side.

[0027]FIG. 9 is a perspective view of the packaging material shown in FIG. 8 when looking from the rear surface side.

[0028]FIG. 10 is a perspective view from the rear surface side showing how recording sheets are stored in the packaging material shown in FIG. 8, with the cap-shaped cover part having been removed.

[0029]FIG. 11 is an unfolding view of the packaging material shown in FIG. 8.

[0030]FIG. 12 is a view, partly in cross-section, showing the sheet package after setting in a printer.

[0031]FIG. 13 is a view, partly in cross-section, showing the sheet package during storage in a printer.

[0032]FIG. 14 is a view, partly in cross-section, showing a state where the recording sheets in the sheet package have been used and few sheets remain in the bundle.

BEST MODE FOR CARRYING OUT THE PRESENT INVENTION

[0033] The following describes, with reference to the attached drawings, an embodiment of the present invention. FIGS. 1 to 3 show one example of the packaging material of the present invention. This packaging material 1 internally holds recording sheets, which in the present example are heat sensitive (thermal) sheets, in a bundle and can be set as it is in a sheet storing part of a printer or in the sheet cassette of a printer. The packaging material 1 of the present example is a sheet or paper cassette in the shape of a slim rectangular solid. The packaging material 1 is made entirely of paper and is around 55 mm lengthwise, 77 mm crosswise, and 5 mm thick. Space for storing around fifty A8-size recording sheets is provided in the packaging material 1.

[0034] As shown in FIG. 3, when a belt-like member 3 is removed from the packaging material 1, a cap-shaped cover part 2, which covers one end of the recording sheets, can be separated from the main part 5. The one end is the sheet feeding side 13 for the recording sheets stored in the packaging material 1. After this, the recording sheets are held in a bundled state by the cylinder-like main part 5 except the one end on the paper feeding side 13. A tongue-like extending part 4 lengthened from the rear surface of the main part 5 towards the one end of the recording sheets on the sheet feeding side 13, and when the belt-like member 3 is removed, the cap-shaped cover part 2 that covers the end of the recording sheets is also separated from the tongue-like extending part 4, so that the cap-shaped cover part 2 that covers the end of the recording sheets can be completely removed from the main part 5 of the packaging material 1. Accordingly, with the packaging material 1 of the present example, the main part 5, which is in the shape of a box or cylinder that is open at the one end is the holding part that holds the recording sheets in a bundle, the cap-shaped part 2 is the cover part that covers the periphery of the one end of the feeding side of the recording sheets. The tongue-like extending or lengthened part 4 that extends from the main part 5 covers at least part of an outer surface of the sheet feeding side 13 of the recording sheets that are held in a bundle by the main part 5, so that when the recording sheets have been set into a printer with the packaging material 1, the tongue-like extending part 4 becomes an underlay for the periphery of the end of the recording sheets in the feeding direction. To make it easy to remove the cap-shaped part 2 from the main part 5 and the tongue-like extending part 4, as shown in FIG. 2 the belt-like member 3 that is the boundary between these parts is provided in advance with two perforated lines 6 that extend along the boundaries between these parts. The belt-like member 3 can be easily separated by simply holding and pulling on a tab 3 a that is slightly lifted off the main part 5.

[0035]FIG. 4 shows the recording sheets 20 that are stored in the packaging material 1 with the cap-shaped cover part 2 that covers the end of the recording sheets having been removed. The packaging material 1 is capable of covering the entire bundle of recording sheets 20 when the cap-shaped part 2 is attached to the main part 5. Before the cap-shaped part 2 is removed from the main part 5, the packaged sheets (sheet package) 21 has the same figure as the packaging material 1 in the state shown in FIGS. 1 and 2 showing the prior state of removing the cap-shaped part 2. The dimensions of the packaging material 1 are set so that the packaging material 1 can fit into the sheet storing space or sheet cassette of a printer. Accordingly, the recording sheets 20 can be set in the printer with the highest number of A8-size recording sheets that can be set at a single time in the sheet storing space or sheet cassette being held in the main part 5 of the packaging material 1.

[0036] With the packaging material 1 of the present example, when the main part 5 of the packaging material 1 is set in the printer with the recording sheets 20 inside, the main part 5 covers the recording sheets 20 except for the end part 20 a of the sheets with which the pickup roller of the printer comes into contact. Prior to set the sheet package 21 in the printer or sheet cassette, the one end part 20 a of the recording sheets 20, which is the paper feeding side 13, is exposed when the cap-shaped part 2 is removed. Therefore, the one end part 20 a of the recording sheets 20 can be brought into contact with the pickup roller with the recording sheets 20 still in a bundle by the main part 5 of the packaging material 1. On the other hand, out of the outer surfaces of the bundled recording sheets 20, on a reverse side (rear side) which is opposite to the side (front side) with which the pickup roller comes into contact, the tongue-like extending part 4 that extends from the main part 5 towards the sheet feeding side 13 acts as an under layer for supporting the lowest sheet 20 c in the bundled recording sheets 20 to the rear side.

[0037] As shown in FIG. 1 or in FIG. 4, an arrow 15 is provided on the surface (front surface or upper surface) 11 of the packaging material 1 for indicating the feeding direction 13 in which the sheets are transported and the correct orientation for insertion into the printer or sheet cassette. A manufacturer name 16 for the manufacturer of the recording sheets stored in the packaging material 1, and various details 17 such as usage conditions, instructions, warnings, a list of the names of compatible printers, and contact information for the manufacturer are also indicated.

[0038] The sheet package 21 is set in the sheet storing space or sheet cassette of a printer with the recording sheets 20 stored in the main part 5. Since the extending part 4 that should be located on the opposite side to the pickup roller is also provided, the orientation of the packaging material 1 to be set is obvious from its shape, which makes it difficult for users to insert the packaging material 1 with the incorrect orientation. In addition, the indication 15 that shows the setting direction is provided on the main part 5, so that even if the user does not know the direction in which the extending part 4 should be set, the user can still definitely set the recording sheets correctly by following the indication 15. In particular, in the case of heat sensitive sheets, photosensitive sheets, or recording sheets that have a surface (“printing surface”) that is suited to ink-jet printing, if the recording sheets are set with an incorrect orientation, printing may not be possible or there may be a marked deterioration in print quality. With the present packaging material 1, however, there is no need to confirm whether the surfaces of the recording sheets are correctly oriented. Also, if the user removes the remaining recording sheets from the cassette and then sets the recording sheets once again, since the recording sheets 20 remain inside the packaging material 1, the recording sheets 20 can be set correctly in accordance with the indication.

[0039] By the specifications 17 provided on the main part 5, the user can refer to the details 17 whenever the user would like to clarify how to set or use the recording sheets 20 before or during a print operation using the recording sheets 20.

[0040] After all of the recording sheets 20 stored in the packaging material 1 have been used, the packaging material 1 remains in the printer or sheet cassette. Accordingly, the user can be prompted to purchase more recording sheets 20 in accordance with the manufacturer name 16 and the details 17 that are indicated on the packaging material 1, so that the user can be prevented from purchasing the wrong recording sheets 20. Also, by indicating the manufacturer name and other information on the packaging material 1, an additional promotional effect is achieved in that the user is encouraged to purchase the same manufacturer's products. It is difficult for a manufacturer to place a mark or the like for immediately identifying the manufacturer on the recording sheets 20 themselves, and difference of properties of recording sheets cannot be distinguished from the appearance of the recording sheets alone. The packaging material 1 merely holds the recording sheets 20 in a bundle and is not printed upon itself, so that it is possible for original designs or color marks to be added or indicated on the packaging material 1. This means that retailers and manufacturers can add their own appeal to users without affecting the recording sheets 20. Other indications aside from advertisements for the manufacturers can be provided on the packaging material 1, so that it is also possible for advertisements for businesses aside from recording sheet and printer manufacturers or suitable indications for commemorative items distributed at an event to be provided.

[0041]FIG. 5 shows the sheet package 21 of the present example after the sheet package 21 has been set in a sheet storing space 37 of a printer 30. This printer 30 is a thermal printer that includes a thermal head 31 and a platen roller 32, with heat sensitive sheets being used as the recording sheets 20. Accordingly, heat sensitive sheets 20 are stored in the sheet package 21, and once the cap-shaped cover part 2 that covers the end has been removed, the one end part 20 a of the heat sensitive sheets 20 become exposed, with the extending part 4 that is elongated from the main part 5 remaining below the bundle of heat sensitive sheets 20 as an underlay. Once the sheet package 21 has been set in the sheet storing space 37 of the printer 30 in this state with the extending part 4 down, the pickup roller 33 contacts the end part 20 a of the heat sensitive sheets 20. When the pickup roller 33 rotates in the sheet feeding direction, a force acts on the heat sensitive sheets 20 in the sheet feeding direction, and the heat sensitive sheets 20 are driven in the paper feeding direction towards the thermal head 31. The one end of the heat sensitive sheets 20 strike a separating wall 34, so that only the top recording sheet 20 that is in contact with the pickup roller 33 is separated and is fed towards the thermal head 31. In the sheet package 21, surfaces 20 b of the recording papers 20 that have been coated with a heat sensitive material are stored facing upwards 11, so that the surface 20 b of the transported recording sheet 20 faces the thermal head 31 and recording sheets 20 that have been printed by the thermal head 31 are outputted from the printer 30.

[0042] In order to maintain the contact pressure between the pickup roller 33 and the recording sheets 20, the printer 30 includes a bottom plate 36 and a spring 35 that presses up the bottom plate 36 towards the pickup roller 33. As shown in FIG. 6, when the recording sheets 20 has been used and the thickness of the remaining bundle of recording sheets 20 falls, the bottom plate 36 moves upwards and so presses up the recording sheets 20 against the pickup roller 33 with an almost constant pressure. In addition, the sheet package 21 has the tongue-like extending part 4 that is lengthened from the main part 5 present as an underlay in between the final recording sheet 20 c and the bottom plate 36. Accordingly, a similar frictional force to the other recording sheets acts on the final recording sheet 20 c, thereby avoiding the case where the final few recording sheets are simultaneously picked up and transported.

[0043]FIG. 7 shows a simplification of the conditions for picking up a recording sheet 20. When the bottom plate 36 is pressed upwards with a force F by the spring 35, a frictional force μF acts so as to transport a recording sheet 20 d where μ is the friction coefficient between the pickup roller 33 and the recording sheet 20 d that is in contact With the pickup roller 33. On the other hand, the recording sheet 20 c that is below the recording sheet 20 d strikes the separating wall 34 and does not move, with a force μF acting between the recording sheet 20 c and the recording sheet 20 d where μi is the friction coefficient between recording sheets. This frictional force μF acts as resistance to the recording sheet 20 d in the sheet feeding direction and as a driving force on the recording sheet 20 c in the sheet feeding direction. When the recording sheet 20 c is the final recording sheet, a force μxF acts between the recording sheet 20 c and the extending part 4 of the sheet package 21 that is the underlay where μx is the friction coefficient between a recording sheet and the extending part 4, with this force μxF acting as resistance to movement of the recording sheet 20 c.

[0044] If the recording sheet 20 c is not the final sheet, since the friction coefficients μi and μx of the frictional forces that act on the recording sheet 20 c are the same, the driving force and resisting force are in balance, so that only the recording sheet 20 d is driven by the pickup roller 33 so as to move in the sheet feeding direction. However, if the friction coefficients μi and μx are not the same, when the frictional force that acts as resistance on the recording sheet 20 c is smaller than the driving force, there is the possibility that this difference in forces will exceed the resistance provided by the separating wall 34. In such cases, the recording sheet 20 c moves together with the recording sheet 20 d above it, so that a plurality of recording sheets 20 are simultaneously picked up and transported towards the thermal head 31. In addition to the wasteful use of recording sheets, this results in a plurality of recording sheets 20 being inserted between the thermal head 31 and the pickup roller 32, which can cause a printer jam. Also, the resulting deviation in the gap between the thermal head 31 and the pickup roller 32 can cause deterioration in print quality and other problems such as a subsequent deterioration in performance relating to the transporting of recording sheets 20. On the other hand, when the friction coefficient of the bottom plate 36 for recording sheets is too high, the driving force provided by the pickup roller 33 becomes insufficient, so that it becomes no longer possible to pick up the final recording sheet.

[0045] When the sheet package 21 is used, the extending part 4 of the packaging material 1 forms an under sheet that is present between the final recording sheet 20 c and the bottom plate 36. This extending part 4 is made of the same kind of paper as the rest of the packaging material 1, so that the friction coefficient μx that acts between the final recording sheet 20 c and the extending part 4 is virtually the same as the friction coefficient μi that acts between recording sheets 20 as resistance to the movement of other recording sheets 20. As there is little change in the conditions for the picking up of the final recording sheet 20 c compared to other recording sheets 20, the final recording sheet 20 c can be reliably prevented from being picked up and transported together with the other recording sheets 20. This means that the recording sheets 20 can be reliably transported one at a time right up to the final recording sheet 20 c.

[0046] When the sheet package 21 having the packaging material 1 is used, the lengthened part 4 is inserted between the final recording sheet and the bottom plate, so as to become an under sheet for the final recording sheet, so that it is no longer necessary to provide a lining material for adjusting the friction coefficient of the bottom plate to that of the sheets. Additionally, since the packaging material 1 is always replaced every time the sheet package 21 is replaced, the friction coefficient of the extending part 4 is always the same as the recording papers 20, so that suitable conditions for picking up recording sheets one at a time can be maintained. Since it is no longer necessary to provide a lining material on the bottom plate of the printer 30, the printer 30 can be made more compact, with there also being a reduction in the manufacturing cost. Since the recording sheets 20 can be reliably picked up one by one and used right up to the final recording sheet 20 c, there is no waste for the recording medium 20, and problems such as printer jams and deterioration in print quality can be prevented. For a compact slimline printer that is suited to portable use, there are limits on the number of storable recording sheets, the ability to reliably use every recording sheet right up to the final sheet is a significant merit.

[0047] The recording sheets 20 that are set in a compact, thin printer are also compact, so that it is difficult to line up the edges of a plurality of such recording sheets 20 and also to set such recording sheets 20 in the sheet storing space of a compact, slimline printer. When the sheet package 21 is used, the recording sheets 20 are already packaged and can be set in the sheet storing space 37 of a compact and thin printer in this bundled state without undoing the bundle. This makes it very easy to handle the recording sheets 20. Accordingly, the recording sheets 20 that are packaged by the packaging material 1, which is the sheet package 21, plays an important role for providing a compact and portable printer having small-size like a postcard or a business card.

[0048] When the sheet package 21 is used, while sheets are being transported to the printer, the recording sheets 20 are held within the packaging material 1 and are in contact with the packaging material 1. By making the packaging material 1 electrically conductive, static electricity that is generated by friction when recording sheets are picked up can be diffused to the outside. If the recording sheets 20 were electrically charged, this can lead to various problems such as dust adhering to the sheets, ink sticking to unintended areas of the sheets, or ink failing to adhere to the sheets. By having the packaging material 1 electrically conductive by mixing a conductive material, such as carbon, in the paper material that composes the packaging material 1, the recording sheets 20 that are held by the packaging material 1 can be directly or indirectly grounded, thereby eliminating the effects of static electricity.

[0049] In the sheet package 21 of the present example, the recording sheets 20 are entirely covered by the packaging material 1 until the cap-shaped part 2 is removed. It is therefore possible to prevent bending or damaging the corners of the recording sheets 20 during storage or transportation. For small-size recording sheets in particular, little leeway is provided in the transportation path inside a printer, so that it is very easy for deformations in the recording sheets to cause printer jams or deterioration in print quality. With the sheet package 21, such problems can be prevented.

[0050]FIG. 8 shows a different sheet package 41 when looking towards the front surface 11. FIG. 9 shows the sheet package 41 when looking towards a rear surface 12. The sheet package 41 of this example is composed of a packaging material 50 that is made of paper and is assembled in the approximate shape of a rectangular solid whose thickness has been reduced to around 2.5 mm. This slimline packaging material 50 is still capable of internally storing around 25 recording sheets. A sufficient number of recording sheets to be set in a compact, portable printer is packaged.

[0051] As shown in an unfolded view in FIG. 11, the packaging material 50 comprises a first member 51 that composes the surface (front surface or upper surface) 11 and when folded along the folds 59 forms a convex shape that provides enough thickness to store the recording sheets, a second member 52 that composes plain, rear surface 12, and a third member 53 that when pasted onto the second member 52 composes the packaging material 50 in the form of a sheet cassette. Both edges 51 a of the first member 51 in the longitudinal direction and both edges 53 a of the third member 53 in the longitudinal direction are formed as pasting margins that extend outwards from a storage part 54 which when assembled is in the shape of a rectangular solid. This means that even for a packaging material 50 that is only around 2.5 mm thick, sufficient margins are provided for attachment, which improves the efficiency of manufacturing of the packages.

[0052] An indication (arrow) 15 for showing the correct orientation (the sheet feeding direction) useful for setting into the printer or sheet cassette is provided on the upper surface 11 of the packaging material 50, along with a manufacturer name 16 and product name or the like. In the part that covers the one end of the stored recording sheets, which is the sheet feeding side 13, a belt-like part 3 that can be removed via two perforated lines is provided along a boundary with the cap-shaped cover part 2. The cover part 2 that has a cap-shape when assembled, can be easily separated by holding and pulling on the tab 3 a.

[0053] As shown in FIGS. 9 and 11, the rear surface 12 has a two-layer construction where the second member 52 and the third member 53 are pasted together. The second member 52 that forms the inside of the rear surface 12 is provided with a tongue-like extending part 4 that extends towards the sheet transportation side 13 from a part 55 a that forms the main part 5 where the recording sheets are held when the packaging material 50 has been assembled. Cuts 57 are provided along the sides of the extending part from the part to which the extending part 4 is attached, these cuts 57 make the long extending part 4. A fold 58 is also provided at the boundary where the extending part 4 and the part 55 a that forms the main body are connected.

[0054] When the packaging material 50 is assembled, the sheet feeding side 13 of the third member 53 forming the outside forms the cap-shaped cover part 2 together with the part of the sheet feeding side 13 of the first member 51. The belt-like member 3, which can be removed via two perforated lines 6, is provided at the boundary between the cover part 2 and the part 55 b that is pasted onto the second member 52 to form the main part 5. The part of the sheet feeding side 13 of the third member 53 from the belt-like member 3 outwards covers the extending part 4 that extends from the fold 58 when the third member 53 has been placed over the second member 52. Accordingly, as shown in FIG. 10, when the user holds the tab 3 a of the belt-like member 3 and separates the cap-shaped cover part 2 from the packaging material 50, the front surfaces 20 b of the recording sheets 20 stored in the packaging material 50 become exposed, and the extending part 4 that extends from the main part 5 on the rear side also appears. The extending part 4 covers the outside of the outermost recording sheet 20 c in the recording sheets 20 that are held in a bundle by the main part 5, so that the extending part 4 acts as an underlay when the sheet package is set in the storing part of a printer.

[0055] The end of the tongue-like extending part 4 is free to move, the sides of the extending part 4 being separated from the main part 5 by the cuts 57 that are provided in advance and the extending part 4 is connected to the main part 5 at the fold 58. This means that the extending part 4 can freely rotate with respect to the main part 5 about the fold 58. When the extending part 4 is pressed upwards by a plate spring or the like that is provided in the printer, the bundled recording sheets 20 deform or are moved in the thickness direction, so that the one end 20 a of the recording sheets 20 stored in the main part 5 can be pressed against the pickup roller.

[0056]FIG. 12 shows how the sheet package 41 of the present example is set in the sheet storing space 37 of a printer 60. FIG. 13 shows the sheet package 41 once it has been set in the printer 60. Like the printer 30 described above, the printer 60 is a thermal printer that includes a thermal head 31 and a platen roller 32, with heat sensitive sheets being used as the recording sheets 20. The printer 60 feeds sheets using the pickup roller 33 disposed on the bottom of a housing 61 in the drawings, with the feeding direction of the recording sheets being reversed around the platen roller 32 that is disposed to the right in the drawings. Once printing has been performed by the thermal head 31, the printed recording sheets 20 are discharged to a stocker 62 that is above the housing 61. To do so, the printer 60 includes a sheet guide 67 that guides recording sheets that have been picked up downwards and guides recording sheets that have been printed upwards, a sheet guide 68 that guides recording sheets around the platen roller 32, and a sheet discharge guide 69 that guides the recording sheets 20 that have been discharged from the housing 61 towards the stocker 62.

[0057] When setting a sheet package 41, as shown in FIG. 12, first the sheet discharge guide 69 is opened and then a cover 63 that forms the stocker 62 above the housing 61 is opened. By that operation, the sheet storing space 37 can be accessed, the sheet package 41 is then set and the cover 63 is closed. This simple operation is sufficient to set the recording sheets in the printer. When the sheet package 41 is set, since the pickup roller 33 is provided on the bottom of the housing 61 in the printer 60, the surface (front surface) 11 where the recording sheets stored in the sheet package 41 are exposed is set facing downwards. In the printer 60, printing is performed after the feeding direction having been changed by 180°, so that the recording sheets are discharged with the printed surfaces facing upwards. The recording sheets 20 are stored in the sheet package 41 with the printing surfaces 20 b of the recording sheets 20 facing the front surface 11, and by merely setting the sheet package 41 in the printer 60 as described above, the recording sheets 20 can definitely be set correctly without the user having to check the front and reverse surfaces of the recording sheets 20.

[0058] With the sheet package 41, it is extremely easy to distinguish between the front surface 11 and the rear surface 12. First, the printed indications 15 and 16 are present on the front surface 11. In addition, the tongue-like extending part 4 is provided on the rear surface 12 that is set on the opposite side to the pickup roller 33. Also, with the sheet package 41 of the present example, the pasted parts 51 a and 53 a extend out like flanges from one of the front surface 11 and the rear surface 12. The user can therefore clearly distinguish between the front surface 11 and the rear surface 12 from these extending parts 51 a and 53 a also. When the sheet package 41 is set in the printer 60, if the sheet package 41 is not set with the correct orientation, the flange-like extending parts 51 a and 53 a strike the housing 61 so that the sheet package 41 cannot be set. The construction of the printer 60 can also be designed so as to prevent the sheet package 41 from being set incorrectly by making it difficult to close the cover 63 when the extending parts 51 a and 53 a point the wrong way.

[0059] As shown in FIG. 13, when the sheet package 41 has been set in the sheet storing space 37 of the printer 60 and the cover 63 is closed, a plate spring 64 provided on the end of the rear surface of the cover 63 strikes the extending part 4 of the sheet package 41 and presses the part 20 a of the sheet feeding end of the recording sheets 20 stored in the sheet package 41 against the pickup roller 33. As shown in FIG. 14, as the recording sheets 20 are consumed and the thickness of the bundle of sheets stored in the packaging material 50 reduces, the extending part 4 that can rotate with respect to the main part 5 about the fold 58 rotates in accordance with the expanding of the plate spring 64. Accordingly, even if the number of recording sheets 20 decreases, the extending part 4 is present as an underlay between the final recording sheet and the plate spring 64, so that pressure can be applied onto the pickup roller 33 right up to the final recording sheet 20. As described in detail for the above embodiments, pressure is applied via the extending part 4 that is made of paper, so that conditions such as the friction coefficient can be kept the same when picking up the final few recording sheets and misfeeds can be prevented.

[0060] When the extending part 4 that extends from the main part 5 was too short, the radius of rotation the extending part 4 becomes shorter when the number of recording sheets 20 has fallen, so that there is the possibility of the end of the extending part 4 being out of the position at which pressure is applied by the plate spring 64. In the sheet package 41 that uses the packaging material 50, cuts 57 are provided on both sides of the extending part 4, so that when the cap-shaped cover part 2 is removed, a suitably long extending part 4 is exposed. The plate spring 64 always applies pressure onto the recording sheets 20 via the extending part 4, and in place of the bottom plate, the extending part 4 applies a suitably distributed force onto the recording sheets 20. The above construction is not limited to using a plate spring, and any member or structure with a suitable elasticity may be used so that the recording sheets 20 apply pressure onto the pickup roller 33 via the extending part 4 that extends from the main part 5. In this case, paper transporting operations for the final few recording sheets can be performed without errors in the same way as was described above.

[0061] Also, while the present invention has been described above using examples where heat sensitive sheets are packaged, there are no limitations regarding the type of recording sheets. Similarly, the present invention is not limited to being applied to thermal printers, and so can be applied to other types of printers, such as ink jet printers and laser printers. For recording sheets such as heat sensitive sheets where there is only one recording surface or other recording sheets where there is a marked difference in print quality between the front and the reverse, the present invention is extremely beneficial since it relieves users of the need to worry about the correct orientation for setting such recording sheets.

[0062] In the printer described above, the pressure applied when picking up recording sheets is maintained by raising and lowering the bottom plate, though the packaging material and sheet packages of the present invention can also be used in a printer or a sheet transporting mechanism where the bottom plate does not move and pressure is instead applied by having the pickup roller move up and down. When the pickup roller is movable, there is no need to make the movable extending part 4 that extends from the main part is move as in the case described above, and the fold is also unnecessary.

[0063] The shape of the packaging material is also not limited to the examples given above. So long as a packaging material includes a main part that can hold recording sheets in a bundled state when stored inside a printer or a sheet cassette and a part that extends from the bottom of the main part in the sheet feeding direction as an under layer, it is possible to manufacture and supply sheet packages where every recording sheet up to the final recording sheet can be reliably used. Accordingly, the main part, which is the part of the packaging material that holds the recording sheets, does not need to be in the shape of a box as in the above examples, and instead can be in the form of a belt that holds a bundle of recording sheets at or near the center of the bundle. However, a package that entirely covers the recording sheets during storage or distribution has the advantage of preventing damage to the corners of the recording sheets, as is described above. Also, while the cap-shaped cover part is separated in the above examples to reveal the one end of the recording sheets, so long as it is possible to remove the cover part without obstructing a sheet feeding operation, it is not necessary for the cover part to be removed by separating it. As one example, if the part that covers the end of the recording sheets is made of an extremely thin material such as cellophane, the sheet package only needs to be opened and sheet feeding operations can be performed unobstructedly without the cover being separated.

[0064] In the above examples, providing perforated lines 6 on both sides of the belt-like member 3 makes it very easy to separate, though separation using simply providing a perforated line with no belt-like part is also possible. Alternatively, the cap-shaped cover part 2 may be attached using thin tape, such as cellophane tape, with the cap-shaped cover part 2 being separated by pulling off such tape. In this way, any suitable means for separating a part of the package may be used. Also, the cover part that covers the one end may be partially connected to the main part, with perforated lines being provided only in the connected part so that the cover part can be removed.

[0065] The extending part 4 that extends or be elongated from the main body does not need to be positioned below the packaged recording sheets when the sheet package is set in a printer or other printing apparatus. It is sufficient for the extending part to be set between the recording sheets and the bottom plate or base of the storing part of the printing apparatus. As shown in FIG. 10, depending on the construction of the printer, the extending part may be positioned above the recording sheets. In the above description, a fold is provided at the position where the extending part 4 is connected to the main part 5 so that the extending part 4 is able to move, though it is possible to make it easy for the extending part 4 to bend by making the connecting part thinner or by providing a concave part. Alternatively, the connecting part between the extending part 4 and the main part 5 may be in the form of bellows or may have a sliding structure that can extend and retract in the thickness direction of the sheet bundle.

[0066] While the present invention has been described by way of a packaging material that is made entirely of paper, with the exception of the tongue-like extending part 4 that should have around the same friction coefficient as paper, the packaging material may be made of another material, such as plastic, vinyl or cellophane. Provided that the surface is treated so as to ensure that the friction coefficient is the same as that of paper, the extending part 4 may be made of a non-paper material, such as plastic. The packaging material of the present invention may be disposable, so that when the surface is treated, it is sufficient for the friction coefficient to last for one use only. On the other hand, the packaging material may alternatively be reusable, with the package being refilled with recording sheets by the user or the manufacturer. However, since there is the possibility of deterioration in the surface characteristics of the extending part used as the underlay, it is most preferable for the packaging to be disposable. A packaging material made of paper is easy to dispose of and is also environmentally friendly. It is also possible for recycled paper to be used, with the packaging also being recycled after use.

[0067] In the above examples, packaging for A8-size recording sheets is described, though the present invention is not limited to A8-size sheets. The present invention may also be applied to packaging for larger recording sheets, such as A4 (210 mm×297 mm) or A3 (297 mm×420 mm) size sheets. However, the present invention is most suited to packaging for A6 and smaller sizes of recording sheets that are used in compact printers, such as printers suited to portable use.

INDUSTRIAL APPLICABILITY

[0068] The packaging material of the present invention includes a holding part that holds recording sheets in a bundle and an extending part that extends from the holding part and is disposed between the bundle of recording sheets and the bottom plate when the packaging material has been set in a printer. Accordingly, with the packaging material of the present invention, small-size recording sheets can be supplied in an easy-to-handle state and packaged recording sheets can be reliably picked up and printed upon right up to the final recording sheet. The present invention is suited to recording sheets that are set in a compact printer, such as a portable printer, where only a limited number of sheets can be stored. 

1. A packaging material, comprising a holding part that holds a plurality of recording sheets in a bundle without holding at least one end of the recording sheets; and an extending part that extends from the holding part so as to cover at least part of one outer surface at the one end of the recording sheets that are held in the bundle by the holding part, wherein a friction coefficient of an inner surface of the extending part that contacts the recording sheets is approximately equal to a friction coefficient of the recording sheets.
 2. A packaging material according to claim 1, wherein at least the extending part is made of paper.
 3. A packaging material according to claim 1, wherein the extending part is connected to the holding part so that a position of the extending part in a thickness direction of the recording sheets held in the bundle by the holding part changes.
 4. A packaging material according to claim 3, wherein the extending part is connected to the holding part via a fold or a part with reduced thickness.
 5. A packaging material according to claim 3, wherein cuts are provided along at least part of side edges of the extending part for moving the extending part independently of the holding part.
 6. A packaging material according to claim 1, further comprising a cover part that covers the one end of the recording sheets that are held in the bundle by the holding part, the cover part being detachable from the extending part.
 7. A packaging material according to claim 6, wherein the cover part is detachable from the holding part.
 8. A packaging material according to claim 7, wherein a boundary of the cover part is perforated.
 9. A packaging material according to claim 8, wherein two perforated lines that form a belt-like part are provided at at least part of the boundary of the cover part.
 10. A packaging material according to claim 1, wherein the holding part and the extending part are made of a conductive material.
 11. A packaging material according to claim 1, wherein the holding part includes a first part that covers an upper surface of the recording sheets held by the packaging material and a second part that covers a lower surface of the recording sheets, with at least part of edges of the first part and the second part extending outwards and being stuck together.
 12. A packaging material according to claim 1, wherein cuts are provided along at least part of side edges of the extending part for moving the extending part independently of the holding part and the packaging material further comprises a cover part that covers the recording sheets that are held in the bundle by the holding part from a periphery of the one end of the recording sheets up to at least the cuts, the extending part becoming exposed when the cover part is separated from the holding part.
 13. Packaged sheets comprising the packaging material according to claim 1 and recording sheets that are stored in the packaging material. 